java - Hibernate 映射文件中的鉴别器值的含义是什么？

Question

<class name="admin.model.OrganizationUnit" table="ORGANIZATION_UNIT" discriminator-value="admin.model.OrganizationUnit" dynamic-update="true">

    <id name="ObjectId" type="string" column="object_id">
        <generator class="assigned"/>
    </id>
    <discriminator column="discriminator"/>
    <property name="ObjectType" type="string">
        <column name="ObjectType" sql-type="varchar2(255)" not-null="true"/>
    </property>

    <subclass name="admin.model.DmSystem" discriminator-value="admin.model.DmSystem" dynamic-update="true">

        <set name="ChildOrgs" lazy="true" table="ORGANIZATION_UNIT" where="ou_type_code='CWORG'">
            <key column="system_org_id"/>
            <one-to-many class="Dm.bizcomponent.admin.model.OrganizationUnit"/>
        </set>

        <set name="SystemAdminAccessGroup" lazy="true" inverse="true" table="CWGROUP" where="group_type_code='SYSTEM_ADMINACCESS'">
            <key column="owner_id"/>
            <one-to-many class="admin.model.Group"/>
        </set>
    </subclass>
</class>

Here is the mapping code In the above code there is one parent Class OrganizationUnit with two subclass

Answer 1

discriminator-value用于确定与基类数据库表中给定数据库行条目关联的实体子类类型的类类型。